The present invention relates generally to lighted window alarms and annunciators and graphic panels.
Many industrial process variables are monitored electronically using thermocouples, transducers and other types of sensors that convert the value of the physical variable being sensed into a logic signal. The temperature and humidity of a computer room are physical variables, for example, and are vital to the proper functioning of computers in those rooms and must be closely monitored. In industry, variables may also include the status of equipment and its physical condition: turbine speed and eccentricity, acidity, pumps being turned on or off, production rates, pressure, etc. Natural conditions such as seismic events are monitored to gather data for the study of earthquakes. Lie detectors monitor the conductivity of the skin as an indirect measure of tension and stress during questioning. Building security systems sense the opening of doors and windows and the presence of excessive heat or smoke in a room or hallway. In these and many other examples, physical measurements are made and conveyed electronically to a receiver, which may passively record the measured data or may actively sound an alarm or light a light to alert the individuals responsible for monitoring the process, condition or event. The receivers of the measured data can be multipoint recorders, automatic controls, data loggers, scanners, controllers and so forth. Many of these devices use microprocessors for receiving and processing the data measurements.
While often physical variables can vary within a normal range without causing concern, it is important to know when a variable goes beyond this nominal range or when the status of equipment changes. Many systems now exist, such as annunciators, for providing this sort of information. However, many are based on relays, configured separately from the receivers and having substantial dimensions even when compactly designed. Many still use incandescent lights for illuminating warning signs, or, if LEDs are used for illumination, they only dimly light the signs. Incandescent lights have a relatively short operating life and are susceptible to failure in an environment where there are vibrations. Many of these units require separate power sources.